Ultrasound probe, ultrasonograph, and ultrasonography

Abstract

A non-invasive (having sufficiently small diameter so as not to give much pain to a subject) ultrasonic ultrasound probe of high spatial resolution and high signal-to-noise ratio, an ultrasonograph using the probe, and an ultrasonography are provided. The ultrasound probe is inserted into the tissue under examination and transmits an ultrasonic wave. The probe is characterized by comprising a hollow outer frame having one of needle shape, a puncture needle portion having the one end and inserted into the tissue of the subject, and an extended portion having the other end, an ultrasonic wave generating source positioned in the hollow part of the extended portion and generating an ultrasonic wave, an acoustic waveguide disposed along the length direction in the hollow part of the outer frame, capable of ultrasonic vibration, and adapted to transmit an ultrasonic wave, and direction changing means for changing the direction of the ultrasonic wave beam transmitted by the acoustic waveguide to the direction toward the position of the tissue under examination.

1. An ultrasound probe adapted to be inserted into body tissue for transmitting ultrasonic waves, said ultrasound probe comprising:
 a hollow outer frame having (i) a needle portion at a distal end region and (ii) an extended portion at the other end region opposite to the distal end region, said needle portion being adapted to be inserted into the body tissue, 
 an ultrasound transducer placed in a bore of said outer frame at said extended portion; 
 an acoustic waveguide located in the bore of said outer frame, said acoustic waveguide being movable in an axial direction of the probe and configured to transmit said ultrasonic wave; and 
 an ultrasound beam deflection device placed in the bore of said outer frame at said needle portion for directing the ultrasonic wave transmitted from said acoustic waveguide to said tissue under examination, 
 wherein 
 the acoustic waveguide has a distal portion with a diameter gradually increasing toward a distal tip end of the distal portion; 
 the ultrasound beam deflection device comprises
 a first mirror (i) having a surface of a part of a paraboloid centered in the axial direction, (ii) placed around the acoustic waveguide so as to envelop the distal portion thereof, and (iii) facing to the distal end region of the needle portion; and 
 a second mirror with a plane or curved surface that reflects the ultrasonic wave that has been reflected by the first mirror toward said tissue under examination. 
 
 
     
     
       2. The ultrasound probe according to  claim 1 , wherein said acoustic waveguide is housed in the bore of said outer frame and is attachable and/or removable from said needle portion along the axial direction. 
     
     
       3. The ultrasound probe according to  claim 1 , further comprising:
 a hollow inner tube in said bore of said outer frame containing the needle portion and the extended portion, 
 wherein said inner tube is removable and repositionable against said needle portion within up to a limited distance along the axial direction, and 
 at least said acoustic waveguide and said ultrasound beam deflection device are housed within said inner tube. 
 
     
     
       4. The ultrasound probe according to  claim 1 , wherein said ultrasound beam deflection device is configured to focus an ultrasonic wave transmitted along said acoustic waveguide. 
     
     
       5. The ultrasound probe according to  claim 1 , further comprising acoustic windows for the transmission of an ultrasound beam directed by said ultrasound beam deflection device, wherein said acoustic windows are provided at a portion of said outer frame and are adapted to be in contact with said tissue under examination. 
     
     
       6. The ultrasound probe according to  claim 1 , wherein at least a part of said acoustic waveguide is made of sapphire or fused quartz. 
     
     
       7. The ultrasound probe according to  claim 1 , further comprising a higher mode of the Pochhammer-Chree wave is that is used as an ultrasonic wave. 
     
     
       8. The ultrasound probe according to  claim 1 , wherein at least a part of said acoustic waveguide is made of the material whose attenuation constant for an ultrasonic wave is substantially equal to or less than that of sapphire or fused quartz in the frequency range from 100 to 200 MHz. 
     
     
       9. The ultrasound probe according to  claim 1 , wherein the diameter of the portion adapted to be inserted into body tissue in said ultrasound probe is less than or equal to 1 mm. 
     
     
       10. An ultrasonograph using a needle-type ultrasound probe for insertion into body tissue, said ultrasonograph comprising:
 said ultrasound probe according to  claim 1 ; and 
 an ultrasound transmitting/receiving means, 
 wherein 
 an ultrasonic wave is transmittable via a surface of said acoustic waveguide and said ultrasound beam deflection device to the tissue under examination, and 
 the ultrasonic wave, reflected by the tissue and received via said ultrasound beam deflection device and via the surface of said acoustic waveguide, is separated and controlled. 
 
     
     
       11. An ultrasonograph using an ultrasound probe for insertion into body tissue, said ultrasonograph comprising:
 said ultrasound probe according to  claim 3 ; 
 a position-controlling means wherein the transmitting position of an ultrasound beam transmitted into the tissue from said ultrasound probe is controlled by moving the position of said acoustic waveguide within said region; and 
 an ultrasound transmitting/receiving means, 
 wherein 
 the ultrasonic wave is transmittable via a surface of said acoustic waveguide and via said ultrasound beam deflection device to the tissue under examination, and 
 the ultrasonic wave reflected from the tissue is received via said ultrasound beam deflection device and via the surface of said acoustic waveguide. 
 
     
     
       12. A method of ultrasonography using a diagnostic device according to  claim 10 , comprising the steps of:
 inserting said ultrasound probe in or close to the tissue under examination; 
 transmitting an ultrasonic wave to said tissue under examination via a surface of said acoustic waveguide and via said ultrasound beam deflection device; 
 receiving the ultrasonic wave reflected from the tissue under examination via said ultrasound beam deflection device and via the surface of said acoustic waveguide; and 
 analyzing a reflected signal after separating the same from the transmitted signal in the received signal. 
 
     
     
       13. A method of ultrasonography using the ultrasonograph according to  claim 11 , comprising the steps of:
 inserting said ultrasound probe in or close to the tissue under examination; 
 transmitting the ultrasonic wave to said tissue under examination via a surface of said acoustic waveguide and via said ultrasound beam deflection device; 
 receiving the ultrasonic wave reflected from said tissue under examination via said ultrasound beam deflection device and via the surface of said acoustic waveguide; 
 controlling the transmitting position of said ultrasound beam so as to scan said tissue under examination using said position-controlling means; and 
 analyzing a reflected signal after separating the same from the transmitted signal in the received signal. 
 
     
     
       14. The ultrasound probe according to  claim 3 , further comprising acoustic windows for the transmission of an ultrasound beam directed by said ultrasound beam deflection device,
 wherein the acoustic windows are provided at a portion of said outer frame and said inner tube and are adapted to be in contact with said tissue under examination. 
 
     
     
       15. The ultrasound probe according to  claim 1 , wherein said ultrasound transducer is connected to a portion of said acoustic waveguide opposite to the distal portion by an acoustic medium which is made of the same material as that of said acoustic waveguide.